The natural enemy of all metal fittings and fixtures in your home is corrosion. Galvanic corrosion can destroy the appearance and functionality of your home’s gutters and downpipes. In this article, Queensland Sheet Metal is discussing how this kind of corrosion occurs and what you can do to prevent it.

Understanding Corrosion and Its Causes

Corrosion is a natural process which converts refined metal to their more stable oxide. This occurs due to the metal’s chemical reactions with the environment, especially when exposed to oxygen. Galvanic corrosion, on the other hand, is an electrochemical process in which one metal corrodes when it is in electrical contact with another, in the presence of an electrolyte.

The problem of galvanic corrosion comes down to using dissimilar metals when they are exposed to water. Some examples of how dissimilar metals may be used in Australian roofing applications include:

  • Stainless steel self-drilling roof screws used to fix Colorbond Steel products
  • Zincalume Steel roof sheeting used in conjunction with lead flashing
  • Galvanised roof sheets mixed with Zincalume roof sheets
  • Black marking pencil on bare galvanised and Zincalume products

Preventing Galvanic Corrosion in Gutters and Downpipes

It’s extremely important to ensure that all bracket fixings and screws used when installing your gutters and downpipes are completely compatible. This also applies if your gutters come into direct contact with plastics, wood or concrete in the roof or walls. These materials can also release corrosive elements that result in metal corrosion. Choosing an experienced company for your installations will prevent these problems.

Additionally, it’s important to understand how certain products interact with and help each other. Zincalume is a metallic-coated steel product that consists of 55% aluminium, 43.5% zinc, and 1.5% silicon. The zinc coating gives it a much longer lifespan than galvanised steel; however, these sheets are incompatible with lead flashing and copper downpipes.

Colorbond uses a Zincalume core with a strong and chip-resistant painted surface. Colorbond Steel has a higher resistance to galvanic corrosion because of the paint layer that covers the reactive Zincalume core. In order to prevent galvanic corrosion in your roofing system, you need to choose products that combat this risk.

Replacing Your Gutters and Downpipes

If you’ve noticed galvanic corrosion on your gutters, downpipes or roofing sheets, it may be wise to replace the entire system with materials that are designed to interact without damaging one another. Queensland Sheet Metal uses Colorbond Steel, Zincalume Steel and MagnaFlow products to create stable and efficient roofing systems that were designed to stand the test of time.

Speak to one of our experienced consultants about your needs today and we’ll work out your best options for new gutters and downpipes. Call us on 1300 926 074 or request a quote online.